Self-collapsing container

ABSTRACT

A self-collapsing thermoplastic container is constructed in such a manner that the walls thereof exert an internal pressure upon the contents in such a manner that upon opening of the discharge outlet the content material may be dispensed.

United States Patent Inventor Julm A. Wlcdenmn 332 W. 37th 51.. NewYork, N.Y. 10018 Appl. No. 879,242 Filed Nov. 24, 1969 Patented Sept.14, 1971 Division of Ser. No. 736,515, May 12, 1968, Pat. No. 3,478,480,which is a division of application Ser. No. 587,511, Oct. 18, 1966, nowPatent No. 3,401,837.

SELF-COLLAPSING CONTAINER 7 Claims, 3 Drawing Figs.

U.S. Cl 222/99 Int. Cl B6541 35/32 Field of Search 222/103,

[56] References (flted UNITED STATES PATENTS 2,989,213 6/1961 Daggitt222/183 X 3,339,809 9/1967 Church et al. 222/215 3,396,876 8/1968Workman et al. 222/183 3,458,087 7/1969 Cox,.lr. 222/99 PrimaryExaminerSamuel F. Coleman Assistant Examiner-Norman L. Stack, Jr.Attorney- Pennie, Edmonds, Morton, Taylor & Adams ABSTRACT: Aself-collapsing thermoplastic container is constructed in such a mannerthat the walls thereof exert an internal pressure upon the contents insuch a manner that upon opening of the discharge outlet the contentmaterial may be dispensed.

PATENIEnsEmmn 31 04595 FIG. 3

IN [/5 N TOR y JOHN A. IEDEMAN SELF-COLLAPSIN G CONTAINER Thisapplication is a division of copending application, Ser. No. 736,515,filed May 12, 1968, now U.S. Pat. No. 3,478,480, which is a division ofcopending application, Ser. No. 587,511, filed Oct. 18, 1966, now U.S.Pat. No. 3,401,837.

This invention relates to flexible collapsible containers. Moreparticularly, the present invention relates to a novel collapsibleplastic container of the type used to contain and dispense toothpaste,creams, medicaments and similar viscous substances, such containersbeing constructed in such manner as to automatically dispense thecontents thereof.

In recent years, a considerable degree of interest has been generated inthe chemical industry for a class of compositions termed thermoplasticmaterials," polyethylene and polypropylene being prime examples of suchcompositions. The inherent advantages of those materials, namely,chemical inertness with respect to contents, ease of ornamentation andnominal cost became evident to workers skilled in the packaging arts andin the years following resulted in an industrial revolution in thepackaging industry.

At an early stage in this revolution, the feasibility of utilizing suchmaterials for packaging toothpaste, cosmetics and the like wasrecognized. Unfortunately, a major prior art difficulty has been theefficient evacuation of the contents of the container. Thus, the normalevacuation or dispensing procedure involves the application by manualmeans of external pressure and in order to assure maximum evacuation thecontainer must be continually squeezed in an inverted position or rolledend upon end (as in the case of thin walled tubes). Unfortunately,neither of those procedures has proven to be entirely satisfactory dueto entrapment of contents or drawing in of air with subsequent lack ofcontrol in dispensing. More recently, a major manufacturer of toothpastecontainers sought to overcome the noted prior art limitations byfurnishing the consumer a slotted key member which facilitates therollup process. However, entrapment of contents as well as air intakestill obtain.

in accordance with the present invention, the prior art limitationsnoted above are effectively obviated by a novel container capable ofcollapsing automatically during expulsion of content material. Theinventive structure is fabricated in such manner that the walls thereofexert an internal pressure upon the content material so that uponexposing the discharge outlet to the external ambient the contentmaterial is automatically dispensed with the concurrent collapse of thecontainer. Application of the desired internal pressure is effected inaccordance with the invention by prestressing and cross linking, thecontainer walls prior to filling, so assuring that the content materialmay be easily advanced through the container and out of the dischargeoutlet of the tube upon removal of the cap while simultaneouslypermitting the automatic collapse of the container. This end iseffectively obtained by selecting a pliant material capable of having aretractile memory generated therein, forming the container configurationof interest and heating the resultant container to a temperatureslightly below the melting point thereof for a time period ranging up to5 minutes, thereby generating the desired retractile memory in thematerial. The container so prepared is then in readiness for fillingwith content material, such end being attained by any of the well-knownprior art procedures.

It will be understood by those skilled in the art that the presentinvention is described for convenience largely in terms of tube contentswherein the container is a cylinder of oval cross section closed at oneend by a heat seal crimp and at the other end by a cap of the stoppertype. However, it will be readily appreciated that such is for purposesof exposition only and that any thermoplastic container may beconstructed as described herein.

The invention will be more readily understood from the followingdetailed description taken in conjunction with the accompanying drawingwherein:

FIG. 1 is a side elevational view of a typical container constructed inaccordance with the invention;

FIG. 2 is a side elevational view of the container of FIG. 1 after aportion of the contents thereof have been dispensed, and

FIG. 3 is a side elevational view of the container of FIG. 2 after thecontainer has been completely evacuated or before being filled.

With reference now more particularly to the drawing wherein likenumerals denote corresponding parts, a collapsible container of the typenormally utilized to contain toothpaste and the like is shown. Shown inthe figures is container 10, said container being essentially a chamberof cylindrical or oval cross section constructed of a thermoplasticmaterial comprising opposite sidewalls and having one end sealed as atwall 11 and the other or discharge end wall provided with a neck portion12 through which a discharge passage or container opening extends. Astopper or cap means is secured in neck 12 in order to prevent theinadvertent escape of contents therethrough until removed by pullingupon tab 13 secured thereto, tab 13 being fastened to neck 12 by meansof an elongated ribbon 14.

As indicated, the subject container which is capable of automaticallycollapsing upon opening of the discharge outlet requires the generationtherein of a retractile memory by prestressing and cross-linking walls15 and 16 thereof, so causing crimped end 11 to coil upon itself as thecontent material is evacuated. This end is most conveniently attained bywinding the thermoplastic container, prior to filling, in helical coilform either about itself or around a mandrel and cross linking it by acontrolled thermal or irradiative technique thereby imparting apermanent coiled configuration to the sidewalls,

thereof.

The thermoplastic material selected for use in the practice of thepresent invention is preferably chosen from among those materialsmanifesting high tensile moduli, that is, a high ratio of stress tostrain in the elastic range of the material. The tensile modulus is adetermining factor in the degree of retractile potential a helicallywound member of given cross-sectional area will possess. Thermoplasticmaterials found useful in the practice of the present invention includepolyethylene, polypropylene, polystyrene, polybutylene,polyvinylchloride, polyamides, etc.

The cross linking and prestressing required herein may typically beeffected by heating the coiled container, as shown in FIG. 3, in asuitable bath, such as water of oil to a temperature just below themelting point thereof, typically 200 C., for a time period ranging up to5 minutes. It will be understood, however, that the specific temperatureemployed is dependent upon the particular thermoplastic materialutilized. Alternatively, this end may be attained by conventionalirradiation techniques such as by means of Van De Graf, cobalt, 60radiation, etc. Following the generation of a retractile memory in tube10, the fluid content material is added by any suitable means, therebyresulting in the unwinding of the container by extension of thesidewalls as caused by the development of internal forces.

The container then has a stopper or cap afiixed thereto and is ready foruse. Upon opening of the container, the content material is dispensedand the walls automatically collapse, by progressively returning to thehelical coil configuration as shown in FIGS. 2 and 3.

Studies of the structures prepared in the foregoing manner haveindicated that ofttimes adverse chemical reactions occur betweencontainer walls and content material. Accordingly, it has been foundadvantageous to coat the interior container walls with a protectivecoating of a material which is inert not only to the container walls butalso to the tube contents, such coating serving as a barrier to themigration of penetrants and/or diffusants and retarding corrosiveaffects attributed to reaction between wall and content material.

The end may effectively be attained by depositing a metal coatingmeeting the above criteria upon the interior container walls by suitablecondensation on plating techniques, vacuum evaporation being eminentlysuited for this purpose. The thickness of the deposited coating is notcritical and may range from about 100-500 Angstroms, such limits beingdictated by practical considerations. The metal most suitable for suchpurposes is aluminum.

Alternatively, it may be desirable to employ a thin coating of athermoplastic material such as polyethylene which does not evidence theobjectionable characteristics of other olefinic.

I claim:

l. A collapsible thermoplastic container for fluid material comprising apair of opposite sidewalls, an end wall and a discharge wall havinghaving a container opening, the walls defining a chamber; the sidewallsof the container being permanently deformed into a helical coilconfiguration and being extendible when fluid contents are introducedinto the chamber, the sidewalls tending to return progressively to thehelical coil configuration to constrain continuously the fluid contentsin a direction toward the container opening.

2. A collapsible thermoplastic container according to claim 1 whereinthe interior of the chamber further includes a protective coating of amaterial which is inert to the thermoplastic material of the containerand to the fluid material to be contained within the chamber.

3. A collapsible thermoplastic container according to claim 2 whereinthe protective coating comprises aluminum.

4. A collapsible thermoplastic container according to claim 2, whereinthe protective coating ranges in thickness from -500 Angstroms.

5. A collapsible thermoplastic container according to claim 1 whereinthe discharge wall further includes a neck portion having a conduitcommunicating with the chamber.

6. A collapsible thermoplastic container according to claim 5 wherein astopper means is removably mounted on the neck portion.

7. A collapsible thermoplastic container according to claim 5 wherein acap means is mounted on the neck portion.

1. A collapsible thermoplastic container for fluid material comprising apair of opposite sidewalls, an end wall and a discharge wall havinghaving a container opening, the walls defining a chamber; the sidewallsof the container being permanently deformed into a helical coilconfiguration and being extendible when fluid contents are introducedinto the chamber, the sidewalls tending to return progressively to thehelical coil configuration to constrain continuously the fluid contentsin a direction toward the container opening.
 2. A collapsiblethermoplastic container according to claim 1 wherein the interior of thechamber further includes a protective coating of a material which isinert to the thermoplastic material of the container and to the fluidmaterial to be contained within the chamber.
 3. A collapsiblethermoplastic container according to claim 2 wherein the protectivecoating comprises aluminum.
 4. A collapsible thermoplastic containeraccording to claim 2, wherein the protective coating ranges in thicknessfrom 100-500 Angstroms.
 5. A collapsible thermoplastic containeraccording to claim 1 wherein the discharge wall further includes a neckportion having a conduit communicating with the chamber.
 6. Acollapsible thermoplastic container according to claim 5 wherein astopper means is removably mounted on the neck portion.
 7. A collapsiblethermoplastic container according to claim 5 wherein a cap means ismounted on the neck portion.